The current program relies heavily on the ability to produce recombinant monoclonal anfibodies by transient transfection. Drs. Steinman and Ravetch will make use of such reagents in targeting DC subsets in vivo and in producing modified anfibodies that are capable of DC targefing and acfivafion. Because they will be used in vivo and in tissue culture experiments uniform quality control for these reagents including LPS tesfing will be crifical. Dr. Nussenzweig will produce hundreds of different human monoclonal anfibodies by the same transfecfion method in his part ofthe program for tesfing in HIV binding and neutralizafion assays. These assays will require hundreds of micrograms of the anfibody reagents. The proposed core will produce recombinant anfibodies for all ofthe participants in the program and in addifion store and distribute the reagents to collaborators and to the scientific community.